The alpine manual says 175mm and from memory that sounds about right. So that might be a bit tight, although with a baffle on it you might just make it?
Are you sure Jim said .01 and not 0.1? I seem to remember the demo Car he had them in were 0.1, and I'm running about .23 I think. I can't really comment on how they would work in much smaller boxes.
As for sound, they are great! I've only has minimal time for Tuning in the 4 weeks I've had off work but they are working out well. Only trouble I'm having is integrating the 12" sub and having it actually contribute much to the sound.
I've had best results so far with the minidsp crossing the 8s and the components at somewhere around 200-250hz 24dB Linkwitz-Riley and they play very happily down to 50hz. With the 12" out of the Car they seem to be almost good enough with no hpf at all. Almost.
They definitely needed a lot more than 150w a side, really came alive with 350w and sweeter still with 450w. Both sides had a nasty peak at about 90hz (left about 6dB and the right about 8dB) but easy to correct. Imaging is quite good too, tho I had to get the components a little more on axis to forget the 8s were on the floor.